中国物理B ›› 2010, Vol. 19 ›› Issue (1): 16301-016301.doi: 10.1088/1674-1056/19/1/016301

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Phonon dispersion relations and soft modes of 4? carbon nanotubes

刘惠军1, 胡懿1, 周详1, 胡承正1, 石兢1, 缪灵2   

  1. (1)Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices (Ministry of Education), Wuhan University, Wuhan 430072, China; (2)Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices (Ministry of Education), Wuhan University, Wuhan 430072, China;Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 43
  • 收稿日期:2008-10-20 修回日期:2009-06-20 出版日期:2010-01-15 发布日期:2010-01-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 10504025), the National Key Basic Research Program of China (Grant No. 2007CB607501), and the Natural Science Foundation for Distinguished Young Scholars of Hubei Province, China.

Phonon dispersion relations and soft modes of 4? carbon nanotubes

Miao Ling(缪灵)a)b), Liu Hui-Jun(刘惠军)a)†, Hu Yi(胡懿)a), Zhou Xiang(周详)a), Hu Cheng-Zheng(胡承正) a), and Shi Jing(石兢)a)   

  1. a Department of Physics and Key Laboratory of Acoustic and Photonic Materials and Devices (Ministry of Education), Wuhan University, Wuhan 430072, China; b Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2008-10-20 Revised:2009-06-20 Online:2010-01-15 Published:2010-01-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 10504025), the National Key Basic Research Program of China (Grant No. 2007CB607501), and the Natural Science Foundation for Distinguished Young Scholars of Hubei Province, China.

摘要: The phonon dispersion relations of three kinds of 4~? carbon nanotubes are calculated by using the density functional perturbation theory. It is found that the frequencies of some phonon modes are very sensitive to the smearing width used in the calculations, and eventually become negative at low electronic temperature. Moreover, two kinds of soft modes are identified for the (5,0) tube which are quite different from those reported previously. Our results suggest that the (5,0) tube remains metallic at very low temperature, instead of the metallic-semiconducting transition claimed before.

Abstract: The phonon dispersion relations of three kinds of 4? carbon nanotubes are calculated by using the density functional perturbation theory. It is found that the frequencies of some phonon modes are very sensitive to the smearing width used in the calculations, and eventually become negative at low electronic temperature. Moreover, two kinds of soft modes are identified for the (5,0) tube which are quite different from those reported previously. Our results suggest that the (5,0) tube remains metallic at very low temperature, instead of the metallic-semiconducting transition claimed before.

Key words: phonon dispersion relations, density functional theory, carbon nanotubes

中图分类号:  (Phonons or vibrational states in low-dimensional structures and nanoscale materials)

  • 63.22.-m
61.46.Fg (Nanotubes) 63.20.D- (Phonon states and bands, normal modes, and phonon dispersion) 71.30.+h (Metal-insulator transitions and other electronic transitions)